Abstract: An IEEE 1394-based unidirectional ring system for an indoor backbone network is disclosed. In the ring system, an RG is used for connection to an external large-capacity network, and an SG is connected to the RG. The SG functions as a clock master to synchronize whole clock signals in the system, manages traffic in the indoor backbone network, manages buses in the indoor backbone network, and monitors the physical states of transmission lines in indoor backbone network. The SG and the SPs form a unidirectional ring structure. A plurality of SPs is configured to load the user data over the indoor backbone network or extract user-desired data from the indoor backbone network to provide user-desired services to a user.

Abstract: A bi-directional wavelength division multiplexing self-healing optical network is disclosed that is constructed of a bi-directional self-healing optical network with one strand of optical fiber which uses a wavelength switching bi-directional add/drop multiplexing unit. The bi-directional wavelength division multiplexing self-healing optical network includes a plurality of nodes. Each of the nodes include a wavelength switching bi-directional add/drop multiplexing section and a switching section for sensing whether at least one optical signal, which is received from a plurality of odd- and even-numbered channel pairs, exists, and for switching such an optical signal to at least one failure-free channel. This allows the optical signals to be transmitted through pairs of failure-free channels when a failure, such as breakage of the optical fiber, takes place.

Abstract: A bi-directional optical add/drop multiplexer is provided comprising a first interleaver for outputting to a second end a forward optical signal that has been inputted through a first end connected to the optical fiber, and a backward optical signal to a second end that has been inputted through a third end; a second interleaver for interleaving the forward optical signal inputted through a first end and the backward optical signal inputted through a second end by wavelengths, and outputting the interleaved signal through a third end; an optical add/drop multiplexing unit for adding a selected channel to the interleaved optical signal or dropping a selected channel from the interleaved optical signal; a third interleaver for outputting a backward optical signal among the channel-modified optical signals inputted through a second end to the third end of the first interleaver through a first end, and a forward optical signal through a third end; and a fourth interleaver for outputting a backward optical signal